KR20130069169A - Construction method for soft removable ground anchor using extension wing attached inner lower body - Google Patents

Abstract

PURPOSE: A construction method of a removing type ground anchor for poor ground using an inner lower body on which an expansion wing is mounted is provided to minimize a loss of a tensile force after tensioning and to improve a drawing resistance force through the resistance of a ground wedge and the resistance of ground pressure of an enlargement bulb. CONSTITUTION: A boring hole is formed in the ground with a casing, and grout is injected into the casing. A ground anchor is inserted into the casing. The casing is pulled out, and an expansion wing(16) is spread with a restitution force of a wing spring and is embedded in the ground. The ground anchor is tensioned through a tension member and reams a predetermined section of the end of the boring hole. Grout is injected into the reamed space so that an enlargement bulb is formed.

Description

Construction method for soft removable ground anchor using Extension wing attached inner lower body}

The present invention relates to a lower body equipped with an expandable wing, a removable ground anchor using the lower body, and a construction method thereof. In particular, the extended wing is automatically spread by the restoring force of a spring, and the soil wedge resistance is inserted into the ground. The load bearing body is equipped with an expandable wing that is designed to increase the pull resistance and minimize the loss of tensile force after tension through the acupressure resistance of the enlarged bulb formed by pressurized grout into the space expanded by the expandable wing. It relates to a removable ground anchor used and its construction method.

Excavation work such as excavation of basement, excavation of bridge foundation and cut of slope is carried out to construct social indirect facilities such as roads, railways and ports, and residential facilities such as buildings and houses.

If the earth pressure generated during the ground excavation can be sufficiently resisted by the shear strength of the ground, no additional reinforcement is necessary on the ground. For example, rock excavation with a very high shear strength of the ground, even when the slope of the cut surface is 90 degrees during rock excavation, the rock does not collapse and secures stability. However, when excavating soft ground with low shear strength of ground at 90 degrees, the ground collapses, so additional reinforcement method is required to secure the stability of the ground.

Ground anchors and soil nailing are the most widely used ground reinforcement methods during excavation. Ground anchors are used for a variety of purposes for temporary reinforcement methods such as temporary earth walls and grounds, to prevent collapse and stabilization of slopes, and to stabilize structures, and are classified into temporary anchors used for short periods of time and permanent anchors used for long periods of time.

In the case of temporary anchors, most anchoring methods are friction anchors, and temporary anchors include buried anchors and removable anchors. Recently, temporary anchors have mostly adopted removable anchors to prevent environmental pollution due to tension members. Removable anchors have various types as below depending on the removal method, mainly U-turn type anchors and soft ground pack anchors are widely used.

As a background art of the present invention, a U-turn type anchor is a removable ground anchor that removes and removes only one of the U shapes when the non-attached strand is bent into a U shape using a load bearing body. At this time, use a crane, hydraulic equipment, etc. to remove the steel wire forcibly. The U-turn type anchor has a problem that it is difficult to apply to the soft ground by expressing the drawing force by the friction resistance of the main surface of the anchor body.

As another background technology of the present invention, the pack anchor is a hypothetical anchor applicable to the soft ground and a ground anchor having a bag-shaped pack (jacket) surrounding the lower body. It supports the load acting on the anchor by using the friction force between the ground and the grout exerted through the expansion of the pack acting as a fixture. Since the pack anchor is a closed injection grouting, it is possible to minimize the loss of the grout material, thereby improving the pull resistance in the soft ground. However, this technique has a problem that the pullout resistance is lowered due to the shrinkage of the grout and the loss of tensile force after tension.

Korean Patent Registration No. 10-0867385 (Registration Date 2008.10.31) discloses an "extended ground anchor structure and its construction method". It is installed in the center of the body and a plurality of expansion plate is rotated around the hinge is installed so that the impact plate is moved upward by the external impact while pushing the catching jaw of the expansion plate to the outside to be embedded in the perforated inner surface Consists of a guide shaft. However, Patent Document 1 has a disadvantage in that the installation structure of the expansion plate is complicated and in the case of soft ground, the pressure resistance of the expansion plate is weak. Korean Unexamined Patent Publication No. 10-2011-0044450 (published April 29, 2011) discloses a "compressed ground anchor structure." This includes a head protrusion to prevent a decrease in adhesion force due to slime during drilling, an anchor head having a separation wall formed between the conical grooves, an injection tube having discharge holes formed therein, a spacer to increase the adhesion and shear force to the inside, and cement. A connecting tube for injecting an injection material such as milk or mortar, a coated strand connected to the conical groove of the spacer and the anchor head through a connecting hose, a fixing band for fixing the coated strand to the anchor, and surrounding the anchor of the configuration It consists of an inflatable pack. However, Patent Document 2 relies only on the pullout resistance that is resisted by the main surface friction of the expandable pack. Therefore, the installation interval of the anchor is widened, so it is difficult to reduce the construction cost and the construction period. In addition, there is a possibility of loss of tensile force after stretching, which deteriorates quality safety after construction.

Therefore, the present invention increases the pull resistance through the soil wedge resistance of the expandable wing is automatically unfolded by the restoring force of the spring and intruding into the ground, and the pressure resistance of the enlarged bulb formed by pressing grout into the space expanded by the expandable wing. It is an object of the present invention to provide a load-bearing body equipped with an expandable wing, a removable ground anchor using the load-bearing body, and a construction method thereof so as to minimize the loss of tensile force after tensioning.

Expanded wing-mounted body according to the present invention for achieving the above object,

A plurality of spacers disposed parallel to each other at a predetermined interval on one axis; A plurality of wing supports disposed at predetermined intervals along a circumference of the outer surfaces of the plurality of spacers; A plurality of expandable wings which are hinged to the plurality of wing supports, respectively, to be opened or folded by a predetermined angle; A plurality of wing springs each installed at a plurality of wing support side hinges and exerting elastic resilience to extend the expandable wing; And it is characterized in that it comprises a tension support head for mounting on the distal end of the plurality of spacers to bind the tension material.

In addition, the spacer is characterized in that the spacer is further installed to space the expansion wing from the slime.

In addition, the plurality of spacers in the form of a hexagonal plate is selected by selecting the four sides facing each other wing support groove is formed, characterized in that the wing support is fitted into the wing support fitting groove is characterized in that the joined.

In addition, the removable ground anchor using a load bearing body equipped with an expandable wing according to the present invention,

A lower body equipped with an expandable wing; It characterized in that it comprises a plurality of tension members are bound in a U-shape to the tension member support head of the inner body to which the expandable wing is mounted.

In addition, the removable ground anchor using a load bearing body equipped with an expandable wing according to the present invention,

A lower body equipped with an expandable wing; A plurality of tension members that are bound in a U shape to the tension member support heads of the inner body to which the expandable wing is mounted; And a packer that wraps the plurality of tension members and expands by filling the grout to generate a perforation hole and major surface friction.

In addition, the construction method of the removable ground anchors using a load bearing body equipped with an expandable wing according to the present invention,

Drilling a hole into a ground using a casing to a required depth to form a hole; Injecting grout into the casing; Inserting a removable ground anchor using an internal body equipped with an expandable wing into a grout-injected casing; Drawing a casing to expand the expandable wings into the ground by expanding with the restoring force of the wing springs; A tensioning step of expanding a predetermined section of the end of the drilled hole by tensioning a removable ground anchor using an inner body equipped with an expandable wing through a tension member; It is characterized in that the construction including the expansion portion grouting step of forming a magnified bulb by pressurizing the grout into the space expanded by the false tension.

In addition, the construction method of the removable ground anchors using a load bearing body equipped with an expandable wing according to the present invention,

Drilling a hole into a ground using a casing to a required depth to form a hole; Injecting grout into the casing; Inserting a removable ground anchor using an internal body equipped with an expandable wing into a grout-injected casing; Drawing a casing to expand the expandable wings into the ground by expanding with the restoring force of the wing springs; Pressing the grout into the packer to bring it into close contact with the perforation hole; A tensioning step of expanding the predetermined section of the perforated hole by tensioning the inner body equipped with the expandable wing until the unfolded expandable wing touches the expanded packer; It is characterized in that the construction including the expansion portion grouting step of forming an enlarged bulb by pressing the grout into the space expanded by the tension of the expandable wing.

Here, the spacer may be installed in a state in which a spacer is further installed to separate the expandable wing from the slime on the tension member support head of the inner body.

An underload body equipped with an expandable wing according to the present invention, a removable ground anchor using the lower load body, and a construction method thereof include earth wedge resistance and an expandable wing in which the expandable wing is automatically unfolded by the restoring force of the spring and inserted into the ground. Through the acupressure resistance of the enlarged bulb formed by filling the grout into the space enlarged by it can increase the pull resistance and minimize the loss of tensile force after stretching. In addition, in soft ground, the additional installation of the packer increases the friction of the principal surface to increase the pull resistance.

Therefore, according to the present invention can be installed by widening the installation interval of the anchor can reduce the construction cost and the construction period can be reduced and there is no loss of tensile force after the tension can ensure the quality after construction to perform a safe and economical construction.

The following drawings, which are attached in this specification, illustrate the preferred embodiments of the present invention, and together with the detailed description thereof, serve to further understand the technical spirit of the present invention. It should not be construed as limited.
1 is a perspective view of the inner body is equipped with an expandable wing according to an embodiment of the present invention.
Figure 2a is a front view of Figure 1 expandable wings folded state.
FIG. 2B is a front view of FIG. 1 showing an extended wing.
Figure 3a is a perspective view of the spacer further installed on the lower body of Figure 1;
FIG. 3B is a front view of FIG. 3A showing an extended wing.
Figure 4a is a front view showing one form of the removable ground anchors using the lower body equipped with an expandable wing according to the present invention.
Figure 4b is a front view showing another form of the removable ground anchor using the inner body equipped with an expandable wing according to the present invention.
Figures 5a to 5d is a process diagram sequentially showing the construction method of the removable ground anchors using a load-bearing body equipped with an expandable wing in the soft ground using Figure 4a.
Figures 6a to 6c is a process diagram sequentially showing the construction method of the removable ground anchors using a load-bearing body equipped with an expandable wing other than the soft ground using Figure 4b.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto.

<Internal Body with Extended Wings>

As shown in FIGS. 1 and 2B, the inner body 10 equipped with the expandable wing includes a plurality of spacers 12 arranged parallel to each other at a predetermined interval on one axis. The plurality of spacers 12 are mounted with wing supports 14 at predetermined intervals along the circumference. In the present embodiment, three spacers 12 are provided, but the present invention is not limited to these numbers.

In this embodiment, the spacer 12 has a hexagonal plate shape. In the spacer 12, wing support fitting grooves 12a are formed on the rectangular periphery thereof, respectively. Of these, the wing supports 14 are fitted into four wing support fitting grooves 12a, and are joined by welding. Therefore, all four wing supports 14 are installed. Wing support 12 has a U-shaped cross section in the longitudinal direction to increase the bending strength. As such, when the four wing supports 12 are mounted on the spacer 12, the inner body of the hexagonal cylindrical shape is formed. The reinforcing bars 13 having the same cross-sectional shape are respectively fitted in the remaining two wing support fitting grooves 12a, and are joined by welding. At least one discharge hole 12b through which the grout is discharged is formed in the wing support 12.

Each lower end of the four wing support 14 is connected to the expandable wing 16 through the hinge 15 to obtain the expansion of the drilling hole and the soil wedge resistance. The hinge 15 may be in the form of a bolt or pin having a circular cross section, for example. The hinge 15 is fixed to the side wall of the wing support 14. The expandable wing 16 is folded in a direction parallel to the wing support 14 with the hinge 15 as the center of rotation. Extended wing 16 has a '?' Shaped cross-sectional structure to have sufficient strength and rigidity to penetrate the ground and resist wedge action.

The expandable wing 16 is rotated by the wing spring 18 so as to be opened while maintaining a constant angle. At this time, the wing spring 18 is installed on the hinge 15, one end is supported by the wing support 14, the other end is supported by the expandable wing 16. The wing spring 18 provides a force that causes the expandable wing 16 to open by elastic restoring force. The maximum spread angle of the expandable blade 16 is limited at the point at which the hinge end of the expandable blade 16 is engaged with the wing support 14. To this end, the hinge end side of the expandable blade 16 has an inclined cross section.

A tension member support head 20 for attaching the tension member 22 in a U shape is mounted on the distal side of the plurality of spacers 12. The tension member supporting head 20 has a semicircular shape having a constant thickness and is connected to the head side plate 21 to prevent the tension member 22 from being separated, and the tension member 22 is bent in a U shape to be connected to the head side plate 21. It has the head curved part 22 of the half-moon shape which guides.

Meanwhile, a spacer 24 may be further installed in the tension member support head 20 to separate the expandable wing 16 from the slime (soil generated at the wall surface of the drilling hole) as shown in FIGS. 3A and 3B. The spacer 24 has a fixed bracket 241 connected to the tension member support head 20 in a U-shape at one end, a circular plate 242 having a disc shape at the other end, a circular plate 242 and a fixed bracket 241. It consists of the shaft 243 to connect. At this time, the size of the circular plate 242 is configured to be smaller than the size of the drilled hole formed in the ground. In addition, the spacer 24 is fixed to the tension member supporting head 20 so that the circular plate 242 is disposed in parallel with the spacer 12.

In addition, the binding band 26 for binding the tension member 22 around the wing support 14 may be further provided. The tie band 26 may be, for example, in the form of a known tieband that tightens a screw to reduce its diameter.

<Removable Ground Anchor Using Internal Loaded Body with Extended Blade and Its Construction Method>

Meanwhile, the removable ground anchor (hereinafter, abbreviated as 'anchor') using the lower body (hereinafter, abbreviated as 'lower body') equipped with the expandable wing may appear in two forms. The first form is an anchor 100A used for the soft ground as shown in FIG. 4A, and the second form is an anchor 100B used in addition to the soft ground as shown in FIG. 4B.

The anchor 100A of the first form is composed of the lower body 10, the tension member 22, and the packer 30, as shown in FIG. 4A, so that the main surface frictional force of the packer 30 in the soft ground, the lower body 10 The combined resistance of the expandable wing and enlarged bulbs increases the pull force.

The tension member 22 has a structure in which a stranded wire is introduced in a state where grease-like oil is filled in the PE tube. At this time, the tension member 22 is connected to the load bearing body 10, as shown in Figure 4a. The tension member 22 is bent in a U-shape to the tension member support head 20 and connected to the lower body 10 by a binding band 26.

The packer 30 is a material that is not easily ruptured when inflated. For example, the packer 30 may be made of silicone rubber or a membrane material. The packer 30 is in the form of a bag and expands in the cross-sectional direction when the grout is filled in the contracted state. The packer 30 has an injection hole for injecting grout.

The construction method in the soft ground using the anchor 100A of the 1st form comprised in this way is demonstrated.

First, the inner body 10 equipped with the expandable wing is connected to the tip injection pipe 5 for inflation injection into the spacer 12 as shown in FIGS. 2A and 2B, and the tension member 22 is the tension support head 20. It is wound on and fixed by the binding band 26, a packer 30 made of silicon rubber, for example, in a predetermined section of the tension member 22 is installed as shown in Figure 4a to prepare for the construction of the ground anchor.

Next, as shown in (a) of FIG. 5A, the hole 100 is formed by drilling the required depth into the ground 100 using the casing 110. At this time, the casing 110 prevents the wall surface of the drilling hole 102 from collapsing and guides the penetration of the drill equipment.

Then, grout is injected into the casing 110 as shown in FIG. 5A (b). The injection method of the grout can be done by gravity, for example, or by pressure through a hose.

Next, the anchor assembly 10 prepared as shown in (a) of FIG. 5b is inserted into the casing 110 into which the grout is injected.

Then, the casing 110 is drawn out as shown in FIG. 5B (b). Accordingly, the expandable wing 16 is unfolded by the restoring force of the wing spring 18 to penetrate the ground, and the casing 110 is removed from the drilling hole.

Next, as shown in (a) of FIG. 5C, the grout is pressed into the packer 30 to be in close contact with the ground. At this time, the injection pressure of the grout may be 5 ~ 8kg / cm ² . By the injection of the grout, the packer 30 expands in the radial direction and is in close contact with the ground of the drilling hole 102. Therefore, a main surface friction force is generated on the surface where the packer 30 and the hole 102 are in contact.

Next, as shown in (b) of FIG. 5 (c), the inner body 10 is stretched until the expanded wing 16 abuts against the enlarged packer 30, thereby expanding a predetermined section of the tip of the drilling hole 102. Has a false tensile stage. At this time, the expandable wing 16 is introduced into the ground and subjected to wedge resistance.

Next, as shown in FIG. 5D, the grout is pressurized into the space 102a enlarged by the false tension of the expandable blade 16 through the tip injection pipe 5 for the expansion part injection to form the enlarged bulb 120. Have a study grouting step. When the expansion part grouting is completed as described above, the pullout resistance of the anchor body is expressed by the combined resistance by the wedge resistance of the expandable wing 16 and the acupressure resistance of the enlarged bulb 120 formed by the expansion part grouting, and the principal surface frictional force of the packer 30. .

Since the tension member 22 is connected to the lower body 10 fixed to the ground can firmly support the retaining wall. That is, the tension member 22 can be tensioned by installing a shim pedestal and a tensioning device to stably support the retaining wall.

After the construction of the retaining wall, the tension member 22 may be separated from the inner body 10. At this time, the stranded wire is drawn in the state in which the grease-like oil is filled in the PE tube, and the tension member 22 is removed, and the inner body 10 equipped with the expandable wing remains separated in the ground.

Here, a spacer 24 may be installed and spaced apart from the slime on the tension member support head 20 of the load bearing body 10.

On the other hand, the anchor 100B of the second form shown in Figure 4b is composed of the lower body 10 and the tension member 22, the expansion wing is entered into the ground to increase the pull resistance and secure the pressure resistance by forming the enlarged bulb It is possible. That is, the anchor 100B of the second form is manufactured in a state in which the packer 30 is removed from the anchor 100A of the first form as shown in FIG. 4B.

Therefore, the anchor 100B of the second form is removed from the packer 30, and may be preferably applied to ground other than the soft ground. Therefore, when looking at the construction method, the step of injecting grout into the packer 30 in the construction method described above is omitted and the rest is made the same. That is, as shown in Figs. 6a to 6c, perforation (Fig. 6a)-> grout injection (Fig. 6a (b))-> Insert the anchor body (Fig. 6b (a))-> Casing drawing (Fig. 6b ( B))-> Angular pseudo-tension (cavity formation) (Fig. 6c (a))-> Magnification bulb formation (Fig. 6c (b)) in the order.

As described above, even when the anchor 100B of the second type is installed in the state in which the packer 30 is removed, the pullout resistance can be exerted by the wedge resistance of the expandable wing 16 and the acupressure resistance of the enlarged bulb 120 formed by the expansion part grouting. have.

As described above, according to the present invention, the pull-out resistance is increased through the resistance of the soil wedge, which is automatically expanded by the restoring force of the spring and is introduced into the ground, and the pressure resistance of the enlarged bulb formed by the grout filling into the space expanded by the expandable wing. It can increase and minimize the loss of tensile force after tensioning. In addition, in soft ground, additional installation of the packer can increase the frictional force of the principal surface, thereby increasing the pull resistance.

Therefore, it is possible to construct by widening the installation interval of the anchor compared to the existing anchor by solving the problem caused by the loss of the tensile force after the tension or when the construction of the ground anchor that is continuously used in the temporary construction during construction and civil works. Therefore, it is possible to reduce the construction cost and shorten the construction period, and there is no loss of tensile force by the main surface frictional resistance and the acupressure resistance after tensioning, so that the quality after construction can be secured and safe and economical construction can be performed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. will be. The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

10: Lower body
12: spacer
12a: fitting groove
14: wing support
16: expandable wing
18: wing spring
20: tension member support head
24: spacer
26: Binding band
30: Packer
102: drill hole
110: casing
120: enlarged bulb

Claims (9)

A plurality of spacers 12 arranged parallel to each other at a predetermined interval on one axis;
A plurality of wing supports 14 disposed at predetermined intervals along the periphery of the outer surfaces of the plurality of spacers 12;
A plurality of expandable wings 16 which are hinged to the plurality of wing supports 14 to be opened or folded by a predetermined angle;
A plurality of wing springs 18 respectively installed at the plurality of wing supports 14 side hinges and exerting elastic repulsive force so that the expandable wing 16 is opened; And
An extension body equipped with an expandable wing, characterized in that it comprises a tension support head (20) for mounting on the distal end of the plurality of spacers (12) to bind the tension member (22). The method of claim 1,
An extension body equipped with an expandable wing, characterized in that a spacer (24) is further installed to space the expandable wing (16) from the slime on the tension support head (20). The method of claim 1,
The plurality of spacers 12 are formed in a hexagonal plate shape by selecting four surfaces facing each other so that the wing support fitting grooves 12a are formed, and the wing support members 14 are fitted into the wing support fitting grooves 12a to be joined. Underload body equipped with an expandable wing, characterized in that. The method of claim 1,
Expandable wing 16 is a load-bearing body equipped with an expandable wing, characterized in that having a 'ㅠ' shaped cross-sectional structure. Claims 1 to 4, wherein the inner body is equipped with an expandable wing consisting of any one of the alternatives;
Removable ground anchors using a load-bearing inner body, characterized in that it comprises a plurality of tension member 22 is attached to the tension member support head 20 of the load-bearing body with the expandable wing in the U-shape. Claims 1 to 4, wherein the inner body 10 is mounted with an expandable wing consisting of any one of the alternatives;
A plurality of tension members (22) which are bound in a U shape to the tension member support head (20) of the inner body to which the expandable wing is mounted; And
Removable ground anchors using an inner body with an expandable wing, characterized in that it comprises a packer (30) surrounding the plurality of tension members (22) is expanded by the filling of the grout to generate a drilling hole and the main surface friction. Using the casing (110) to drill the required depth into the ground (100) to form a hole (102);
Injecting grout into the casing (110);
Inserting a removable ground anchor (100B) using the extended wing-mounted inner body of claim 5 into the grout-injected casing (110);
Drawing the casing 110 to expand the wing 16 into the ground by expanding the restoring force of the wing spring 18;
A tensioning step of expanding a predetermined section of the perforated hole 102 by tensilely tensioning the removable ground anchor 100B using a load-bearing body equipped with an expandable wing through the tension member 22;
A method of constructing a removable ground anchor using an underloaded body equipped with an expandable wing, comprising an expansion part grouting step of pressurizing a grout into a space expanded by a false tension to form an enlarged bulb. Using the casing (110) to drill the required depth into the ground (100) to form a hole (102);
Injecting grout into the casing (110);
Inserting the removable ground anchor (100A) using the extended wing-mounted inner body of claim 6 into the grout-injected casing (110);
Drawing the casing 110 to expand the wing 16 into the ground by expanding the restoring force of the wing spring 18;
Pressing the grout into the packer 30 so as to be in close contact with the drilling hole;
Underloading tension stage to expand a certain section of the tip of the drilling hole 102 by stretching the lower body 10 equipped with the expandable wing until the unfolded expandable wing 16 abuts the expanded packer 30; ;
Removable ground anchors using an internal body equipped with an expandable wing characterized in that it is constructed, including an expansion part grouting step of pressurizing the grout into the space expanded by the tension of the expandable wing 16 to form an enlarged bulb. Construction method. 9. The method according to claim 7 or 8,
Using the expandable blade-mounted inner body, which is constructed in a state in which the spacer 24 is further installed to separate the expandable wing 16 from the slime on the tension member support head 20 of the load-bearing body 10. Construction method of removable ground anchor.

Images